The invention relates to novel substituted N-benzoyl-N'-2,3,5-trihalo-4-haloalkoxyphenylureas of formula I ##STR1## wherein R.sub.1 is CF.sub.3, CF.sub.2 CF.sub.3 or CF.sub.2 F.sub.2 CF.sub.3, to the preparation of these compounds and to intermediates for their synthesis. The invention further relates to the use of the novel compounds for use in pest control and to pesticidal compositions which contain at least one compound of formula I as active component. The preferred utility is the control of pests of animals and plants.

The present invention relates to novel substituted N-benzoyl-N'-2,3,5-trihalo-4-haloalkoxyphenylureas, to a process for theirpreparation and to intermediates for their synthesis, to pesticidal compositions which contain these novel compounds and to the use thereof in pest control.

The novel compounds have the formula I ##STR2## wherein R.sub.1 is CF.sub.3, CF.sub.2 CF.sub.3 or CF.sub.2 CF.sub.2 CF.sub.3.

Among the compounds of formula I, the preferred compound is that in which R.sub.1 is CF.sub.2 CF.sub.3.

The compounds of this invention can be prepared by methods which are known per se. Such methods are disclosed, for example, in German Offenlegungsschrift specifications 2 123 236, 2 601 780 and 3 240 975. Thus, for example, the compounds offormula I can be obtained by

a) reacting an aniline of formula II ##STR3## with the benzoyl isocyanate of formula III ##STR4## or

b) reacting an isocyanate of formula IV ##STR5## with the benzamide of formula V ##STR6## or

c) reacting an aniline of formula II with a urethane of formula VI ##STR7## In formulae II and IV above R.sub.1 is as defined for formula I and, in formula VI, R is a C.sub.1 -C.sub.8 alkyl radical which is unsubstituted or is substituted byhalogen, preferably chlorine.

The above processes a), b) and c) can preferably be carried out under normal pressure and in the presence of an organic solvent or diluent. Examples of suitable solvents or diluents are: ethers and ethereal compounds such as diethyl ether,dipropyl ether, dibutyl ether, dioxane, dimethoxyethane and tetrahydrofuran; N,N-dialkylated carboxamides; aliphatic, aromatic and halogenated hydrocarbons, preferably benzene, toluene, xylene, chloroform, methylene chloride, carbon tetrachloride andchlorobenzene; nitriles such as acetonitrile or propionitrile; dimethyl sulfoxide; and ketones, e.g. acetone, methyl ethyl ketone, methyl isopropyl ketone and methyl isobutyl ketone. Process a) is normally carried out in the temperature range from-10.degree. to +200.degree. C., preferably from 0.degree. to 150.degree. C., if desired in the presence of an organic base, e.g. triethylamine. Process b) is carried out in the temperature range from 0.degree. to 150.degree. C., preferably at theboiling point of the solvent employed and, if desired, in the presence of an organic base such as pyridine, and/or with the addition of an alkali metal or alkaline earth metal, preferably sodium. For the reaction of the urethane of formula VI with ananiline of formula II according to process c), a temperature range from about 60.degree. C. to the boiling point of the reaction mixture is preferred, and the solvent employed is preferably an aromatic hydrocarbon such as toluene, xylene, chlorobenzeneand the like.

The starting materials of formulae III to VI are known or can be prepared by methods analogous to known ones.

The starting materials of formula II are novel compounds, which also constitute an object of the present invention. The compounds of formula II can be prepared in a manner known per se, for example by hydrogenating a suitably substitutednitrobenzene of formula VII ##STR8## in a manner analogous to that described in J. Org. Chem. 29 (1964), 1, (q.v. also the literature cited in this reference). However, anilines of formula II can also be obtained by chemical reduction (e.g. with Sn(II)chloride/HCl) of the corresponding nitro compounds of formula VII (q.v. Houben-Weyl, Methoden d. org. Chemie, 11/1, 422). A further means of preparing anilines of formula II comprises appropriately haloalkylating free or acylated2-fluoro-3,5-dichloro-4-hydroxyaniline and then removing the acyl group, if present, for example by acid hydrolysis.

The nitro compounds of formula VII are likewise novel and constitute an object of the present invention. They can be obtained, for example, by appropriate haloalkylation of 2-fluoro-3,5-dichloro-4-nitrophenol (q.v. French patent specification 2005 876) or by reaction of 2,4-difluoro-3,5-dichloronitrobenzene with a suitable polyfluoroalkanol in alkaline solution and dimethyl sulfoxide as solvent (q.v. "The Chemistry of the Hydroxyl Group", pp. 83-124, Interscience Publishers Inc., New York,1971).

The benzoylisocyanate of formula III can be obtained, for example, as follows (q.v. J. Agr. Food Chem. 21, 348 and 993; 1973): ##STR9## The 4-(polyfluoroalkoxy)phenylisocyanates of formula IV can be prepared, for example, by phosgenating ananiline of formula II by methods which are commonly known in the art. The benzamide of formula V also employed as starting material is known (q.v. for example Beilstein, "Handbuch der organischen Chemie", Vol. 9, p. 336).

The urethane of formula VI can be obtained in a manner known per se by reacting the benzoylisocyanate of formula III with a suitable alcohol or by reacting the benzamide of formula V, in the presence of a base, with a corresponding ester ofchloroformic acid Cl--COOR.

Published European patent application 0 071 279 broadly discloses, for example, N-halobenzoyl-N'-(halo-4-haloalkoxy)phenylureas as insecticides with larvacidal activity. Published European patent application 0 194 688 also broadly disclosesN-dihalobenzoyl-N'-(halo-4-fluoroalkoxy)phenylureas as insecticides with ovicidal and larvicidal activity. In neither of these two publications, however, are N-(2,6-difluorobenzoyl)-N'-(2-fluoro-3,5-dichloro-4-trifluoroethoxy, -pentafluoropropoxy or-heptafluorobutoxy)phenylureas specifically disclosed.

Surprisingly, it has been found that the compounds of formula I of this invention are more effective pesticides while being well tolerated by warm-blooded animals and plants. The compounds of formula I are therefore suitable e.g. for controllingpests of animals and plants. Such pests belong principally to the phylum of Arthropoda, such as in particular insects of the orders Lepidoptera, Coleoptera, Homoptera, Heteroptera, Diptera, Thysanoptera, Orthoptera, Anoplura, Siphonaptera, Mallophaga,Thysanura, Isoptera, Psocoptera or Hymenoptera and arachnids of the order Acarina, e.g. mites and ticks. Every development stage of the pests can be controlled, i.e. the adults, pupae and nymphs, and also in particular the larvae and eggs. It is thuspossible to control effectively in particular larvae and eggs of phytopathogenic insect pests and mites in crops of ornamentals and useful plants, e.g. in fruit and vegetable crops, and especially in cotton crops. If compounds of formula I are ingestedby imagines, then a direct kill of the pests or a reduced oviposition and/or hatching rate can be observed. This last activity can be observed in particular in Coleoptera. In the control of pests that are parasites of animals, in particular of domesticanimals and productive livestock, the chief pests are ectoparasites, such as mites and ticks and Diptera, for example Lucilia sericata.

In particular the compounds of this invention are distinguished by their excellent larvicidal action against Spodoptera littoralis and Heliothis virescens.

The good pesticidal activity of the compounds of formula I corresponds to a mortality of at least 50-60% of the above pests.

The activity of the compounds of formula I and of the compositions containing them can be substantially broadened and adapted to prevailing circumstances by addition of other insecticides and/or acaricides. Examples of suitable additivesinclude: organophosphorus compounds, nitrophenols and derivatives thereof, formamidines, ureas, carbamates, pyrethroids, chlorinated hydrocarbons, and Bacillus thuringiensis preparations.

The compounds of formula I are used in unmodified form, or preferably together with the inert, agriculturally acceptable adjuvants conventionally employed in the art of formulation, and can therefore be formulated in known manner to emulsifiableconcentrates, directly sprayable or dilutable solutions, dilute emulsions, wettable powders, soluble powders, dusts, granulates, and also encapsulations in e.g. polymer substances. As with the compositions, the methods of application such as spraying,atomising, dusting, scattering or pouring, are chosen in accordance with the intended objectives and the prevailing circumstances.

The formulations, i.e. the compositions, preparations or mixtures containing the compound (active ingredient) of formula I or combinations thereof with other insecticides or acaricides, and, where appropriate, a solid or liquid adjuvant, areprepared in known manner, e.g. by homogeneously mixing and/or grinding the active ingredients with extenders, e.g. solvents, solid carriers and, in some cases, surface-active compounds (surfactants).

Suitable solvents are: aromatic hydrocarbons, preferably the fractions containing 8 to 12 carbon atoms, e.g. xylene mixtures or substituted naphthalenes, phthalates such as dibutyl phthalate or dioctyl phthalate, aliphatic hydrocarbons such ascyclohexane or paraffins, alcohols and glycols and their ethers and esters, such as ethanol, ethylene glycol, ethylene glycol monomethyl or monoethyl ether, ketones such as cyclohexanone, strongly polar solvents such as N-methyl-2-pyrrolidone, dimethylsulfoxide or dimethylformamide, as well as vegetable oils or epoxidised vegetable oils such as epoxidised coconut oil or soybean oil; or water.

The solid carriers used e.g. for dusts and dispersible powders are normally natural mineral fillers such as calcite, talcum, kaolin, montmorillonite or attapulgite. In order to improve the physical properties it is also possible to add highlydispersed silicic acid or highly dispersed absorbent polymers. Suitable granulated adsorptive carriers are porous types, for example pumice, broken brick, sepiolite or bentonite; and suitable nonsorbent carriers are materials such as calcite or sand. In addition, a great number of pregranulated materials of inorganic or organic nature can be used, e.g. especially dolomite or pulverised plant residues.

Depending on the nature of the compound of formula I to be formulated, or of combinations thereof with other insecticides or acaricides, suitable surface-active compounds are non-ionic, cationic and/or anionic surfactants having good emulsifying,dispersing and wetting properties. The term "surfactants" will also be understood as comprising mixtures of surfactants.

Suitable anionic surfactants can be both water-soluble soaps and water-soluble synthetic surface-active compounds.

Suitable soaps are the alkali metal salts, alkaline earth metal salts or unsubstituted or substituted ammonium salts of higher fatty acids (C.sub.10 -C.sub.22), e.g. the sodium or potassium salts of oleic or stearic acid, or of natural fatty acidmixtures which can be obtained e.g. from coconut oil or tallow oil. Further suitable surfactants are also the fatty acid methyltaurin salts as well as modified and unmodified phospholipids.

The fatty sulfonates or sulfates are usually in the form of alkali metal salts, alkaline earth metal salts or unsubstituted or substituted ammonium salts and contain a C.sub.8 -C.sub.22 alkyl radical which also includes the alkyl moiety of acylradicals, e.g. the sodium or calcium salt of lignosulfonic acid, of dodecylsulfate, or of a mixture of fatty alcohol sulfates obtained from natural fatty acids. These compounds also comprise the salts of sulfated and sulfonated fatty alcohol/ethyleneoxide adducts. The sulfonated benzimidazole derivatives preferably contain 2 sulfonic acid groups and one fatty acid radical containing 8 to 22 carbon atoms. Examples of alkylarylsulfonates are the sodium, calcium or triethanolamine salts ofdodecylbenzenesulfonic acid, dibutylnaphthalenesulfonic acid, or of a condensate of naphthalenesulfonic acid and formaldehyde. Also suitable are corresponding phosphates, e.g. salts of the phosphoric acid ester of an adduct of p-nonylphenol with 4 to 14moles of ethylene oxide.

Non-ionic surfactants are preferably polyglycol ether derivatives of aliphatic or cycloaliphatic alcohols, or saturated or unsaturated fatty acids and alkylphenols, said derivatives containing 3 to 30 glycol ether groups and 8 to 20 carbon atomsin the (aliphatic) hydrocarbon moiety and 6 to 18 carbon atoms in the alkyl moiety of the alkylphenols.

Cationic surfactants are preferably quaternary ammonium salts which contain, as N-substituent, at least one C.sub.8 -C.sub.22 alkyl radical and, as further substituents, unsubstituted or halogenated lower alkyl, benzyl or hydroxy-lower alkylradicals. The salts are preferably in the form of halides, methylsulfates or ethylsulfates, e.g. stearyltrimethylammonium chloride or benzyldi(2-chloroethyl)ethylammonium bromide.

The pesticidal compositions usually contain 0.1 to 99%, preferably 0.1 to 95%, of a compound of formula I or a combination thereof with other insecticides or acaricides, 1 to 99.9% of a solid or liquid adjuvant, and 0 to 25%, preferably 0.1 to20%, of a surfactant.

Whereas commercial products are preferably formulated as concentrates, the end user will normally employ diluted formulations of substantially lower concentration.

The compositions may also contain further ingredients, such as stabilisers, antifoams, viscosity regulators, binders, tackifiers as well as fertilisers or other active ingredients for obtaining special effects.

12.4 g of 90% potassium hydroxide are suspended in 80 ml of dimethyl sulfoxide. With stirring, 30 g of 2',2',3',3',3'-pentafluoropropanol are added dropwise to this suspension. The resultant solution is then added dropwise at room temperature,with stirring, to a solution of 52.4 g of 2,4-difluoro-3,5-dichloronitrobenzene in 150 ml of dimethyl sulfoxide. When the dropwise addition is complete, the reaction mixture is stirred for 2 hours at room temperature and then concentrated. The crudeproduct is dissolved in methylene chloride and the methylene chloride solution is washed with water and dried and, finally, the solvent is distilled off. The crude product is purified by chromatography through a column of silica gel using a 19:1 mixtureof hexane/ether as eluant. The solvent is then distilled off, affording yellow crystals of the title compound of formula ##STR10## with a melting point of 62.degree.-63.degree. C.

6.2 g of the above nitrobenzene are dissolved in 60 ml of tetrahydrofuran and the solution is hydrogenated at room temperature for 8 hours in the presence of 2 g of Raney nickel (H.sub.2 absorption: 1.2 l). The reaction mixture is filtered, thesolvent is distilled off, and the residue distilled. The title compound of formula ##STR12## has a boiling point of 170.degree. C./0.06 torr.

A solution of 3.3 g of 2,6-difluorobenzoylisocyanate in 10 ml of dry toluene is added to a solution of 2-fluoro-3,5-dichloro-4-(2',2',3',3',3'-pentafluoropropoxy)aniline in 50 ml dry toluene, and the mixture is stirred for 10 hours. Then about75% of the solvent is removed in a rotary evaporator. The precipitate is filtered with suction, washed with a small amount of cold toluene and hexane and dried under vacuum, affording the title compound of formula ##STR14## in the form of a whitecrystalline powder with a melting point of 176.degree.-179.degree. C.

The active ingredient is thoroughly mixed with the adjuvants and the mixture is thoroughly ground in a suitable mill, affording wettable powders which can be diluted with water to give suspensions of the desired concentration.

The finely ground active ingredient is intimately mixed with the adjuvants, giving a suspension concentrate from which suspensions of any desired concentration can be obtained by dilution with water.

EXAMPLE 3

Biological Tests

3.1. Action against Musca domestica

50 g of freshly prepared nutrient substrate for maggots are weighed into a beaker. Then 5 ml of a 1% acetonic solution of the test compound are pipetted onto the nutrient substrate present in the beaker. The substrate is then thoroughly mixedand the acetone subsequently allowed to evaporate over a period of at least 20 hours.

Then 25 one-day-old maggots of Musca domestica are put into the beaker containing the treated nutrient substrate. After the maggots have pupated, the pupae are separated from the substrate by flushing them out with water and then deposited in acontainer closed with a perforated top.

The flushed out pupae are counted to determine the toxic effect of the test compound on the maggot development. A count is then made after 10 days of the number of flies which have hatched out of the pupae.

The compounds of Example 1.2. exhibit good activity in this test.

3.2. Action against Lucilia sericata

1 ml of an aqueous solution containing 0.5% of test compound is added at 50.degree. C. to 9 ml of a culture medium. Then about 30 freshly hatched Lucilia sericata larvae are added to the culture medium, and the insecticidal action is determinedafter 48 and 96 hours by evaluating the mortality rate.

In this test, compounds of Example 1.2. exhibit good activity against Lucilia sericata.

3.3. Action against Aedes aegypti

A specific amount of a 0.1% solution of the test compound in acetone is pipetted onto the surface of 150 ml of water in a beaker to give a concentration of 12.5 ppm. After the acetone has evaporated, 30 to 40 two-day-old larvae of Aedes aegyptiare put into the beaker containing the test compound. Mortality counts are made after 2 and 7 days.

In this test, compounds of Example 1.2. exhibit good activity against Aedes aegypti.

Cotton plants in the cotyledon stage are sprayed with an aqueous emulsion (obtained from a 10% emulsifiable concentrate) containing 3, 1.5, 0.8, 0.4 and 0.2 ppm of the test compound. After the spray coating has dried, each cotton plant ispopulated with Spodoptera littoralis and Heliothis virescens larvae in the L.sub.1 -stage. The test is carried out at 26.degree. C. and ca. 50% relative humidity. After 6 days a mortality count is made of the larvae present on the plants.

Potted soybean plants (pot size: 10 cm diameter) in the 4-leaf stage are sprayed with aqueous emulsions which contain the test compound in a concentration of 0.75 ppm.

After 2 days, each treated soybean plant is populated with 10 larvae of Spodoptera littoralis and Heliothis virescens in the L.sub.3 -stage. The test is carried out at 26.degree. C. and ca. 60% relative humidity in dim light. After 2 and 5days evaluation is made to determine the percentage mortality of the larvae.

Compounds of Example 1.2. effect 80-100% kill against Spodoptera and Heliothis after 2 and 5 days.

Potted Chinese cabbage plants (pot size: 10 cm diameter) in the 4-leaf stage are sprayed with aqueous emulsions which contain the test compound in a concentration of 0.75 ppm.

After 2 days, each treated Chinese cabbage plant is populated with 10 Plutella xylostella larvae in the L.sub.2 -stage. The test is carried out at 26.degree. C. and ca. 60% relative humidity in dim light. After 2 and 5 days evaluation is madeto determine the percentage mortality of the larvae.

Compounds of Example 1.2. effect 80-100% kill after 2 and 5 days.

3.7. Action against Laspeyresia pomonella (eggs)

Egg deposits of Laspeyresia pomonella not more than 24 hours old are immersed on filter paper for 1 minute in an aqueous acetonic solution containing 400 ppm of the test compound.

After the solution has dried, the eggs are placed in petri dishes and kept at a temperature of 28.degree. C. The percentage of larvae hatched from the treated eggs is evaluated after 6 days.

The compounds of Example 1.2. exhibit good activity in this test.

3.8. Influence on the reproduction of Anthonomous grandis

Anthonomous grandis adults which are not more than 24 hours old after hatching are transferred in groups of 25 to barred cages. The cages are then immersed for 5 to 10 seconds in an acetonic solution containing 0.1% by weight of the testcompound. After the beetles have dried, they are placed in covered dishes containing feed and left for copulation and oviposition. Egg deposits are flushed out with running water twice to three times weekly, counted, disinfected by putting them for 2to 3 hours into an aqueous disinfectant, and then placed in dishes containing a suitable larval feed. A count is made after 7 days to determine whether larvae have developed from the eggs.

The duration of the reproduction inhibiting effect of the test compounds is determined by monitoring the egg deposits over a period of about 4 weeks. Evaluation is made by assessing the reduction in the number of deposited eggs and hatchedlarvae in comparison with untreated controls.

The compounds of Example 1.2. exhibit a good reproduction inhibiting effect in this test.

3.9. Action against Anthonomus grandis (adults)

Two cotton plants in the 6-leaf stage, in pots, are each sprayed with a wettable aqueous emulsion formulation containing 100 ppm of the test compound. After the spray coating has dried (about 11/2 hours), each plant is populated with 10 adultbeetles (Anthonomus grandis). Plastic cylinders, covered at the top with gauze, are then slipped over the treated plants populated with the test insects to prevent the beetles from migrating from the plants. The treated plants are then kept at25.degree. C. and about 60% relative humidity. Evaluation is made after 2, 3, 4 and 5 days to determine the percentage mortality of the beetles (percentage in dorsal position) as well as the anti-feeding action as compared with untreated controls.

Compounds of Example 1.2. exhibit good activity in this test.

3.10. Action against Epilachna varivestis

Phaseolus vulgaris plants (dwarf beans) about 15-20 cm in height are sprayed with aqueous emulsion formulations of the test compound in concentrations of 800 ppm. After the spray coating has dried, each plant is populated with 5 larvae ofEpilachna varivestis (Mexican bean beetle) in the L.sub.4 -stage. A plastic cylinder is slipped over the treated plants and covered with a copper gauze top. The test is carried out at 28.degree. C. and 60% relative humidity. The percentage mortalityis determined after 2 and 3 days. Evaluation of feeding damage (anti-feeding effect), and of inhibition of development and shedding, is made by observing the test insects for a further 3 days.

Appropriate amounts of a wettable powder formulation containing 25% by weight of the test compound are mixed with sufficient water to produce an aqueous emulsion with an active ingredient concentration of 400 ppm. One-day-old egg deposits ofHeliothis on cellophane and egg deposits of Spodoptera on paper are immersed in these emulsions for 3 minutes and then collected by suction on round filters. The treated deposits are placed in petri dishes and kept in the dark at 28.degree. C. and 60%relative humidity. The hatching rate, i.e. the number of larvae that have hatched from the treated eggs, in comparison with untreated controls is determined after 5 to 8 days.